linux-kernel - [PATCH 2/3] drm/dp_mst: Fix potential topology ref leak in drm_dp_atomic_find_vcpi

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Date:   Wed, 16 Jan 2019 15:37:58 -0500
From:   Lyude Paul <lyude@...hat.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Daniel Vetter <daniel@...ll.ch>, David Airlie <airlied@...ux.ie>,
        Harry Wentland <harry.wentland@....com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] drm/dp_mst: Fix potential topology ref leak in drm_dp_atomic_find_vcpi_slots()

This is a very minute issue I introduced that I just noticed when
scrolling through drm_dp_mst_topology.c: if a driver uses
drm_dp_atomic_find_vcpi_slots() incorrectly, we'll forget to release the
topology reference we grabbed on port.

So, fix this by jumping to 'out' instead of returning -EINVAL
immediately.

Signed-off-by: Lyude Paul <lyude@...hat.com>

Fixes: eceae1472467 ("drm/dp_mst: Start tracking per-port VCPI allocations")
Cc: Daniel Vetter <daniel@...ll.ch>
Cc: David Airlie <airlied@...ux.ie>
Cc: Harry Wentland <harry.wentland@....com>
Signed-off-by: Lyude Paul <lyude@...hat.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 49575b80caeb..d99560c5c693 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3070,7 +3070,8 @@ int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
 			if (WARN_ON(!prev_slots)) {
 				DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
 					  port);
-				return -EINVAL;
+				ret = -EINVAL;
+				goto out;
 			}
 
 			break;
-- 
2.20.1